Kaiken?

[katonk66]

Curious as to what this mei/gimei says?

[ChrisW]

How thick is the mune of the blade near the machi?

[ROKUJURO]

Henry,

looks like a small TANTO with BIZEN MEI. To make reading easier for us, please post NAKAGO photos always vertically, tip upwards. Ideally with light from the side and with a dark background.

[katonk66]

[katonk66]

36 minutes ago, ChrisW said:

How thick is the mune of the blade near the machi?

About 6mm behind the "notch"

[Bugyotsuji]

I can see 備前長船 Bizen Osafune... on one side and 天正 Tensho (?)X 年月日on the other.

[ChrisW]

I ask because if it is fairly thick, then it might be considered a yoroi-doshi aka an "armor piercing" tanto. But this appears to be a normal tanto. I wouldn't call it a kaiken unless it comes in appropriate koshirae. It is the koshirae that makes a kaiken what it is if I recall correctly.